/*
   @Copyright:LeetCode
   @Author:   tjyemail
   @Problem:  http://leetcode.com/problems/climbing-stairs
   @Language: C++
   @Datetime: 19-07-02 14:12
   */

class Solution {
public:
	int climbStairs(int n) {
		int f=1;
		for(int l=0; n--; f+=l, l=f-l);
		return f;
	}
};
